My weekly routine is generally this:
~1: get fresh produce from the farmers market. I also buy cornmeal, brown rice, and milk there. If I make it there early enough before supplies run out, there are eggs and meat available as well.
~2: plan meals for the week based on our haul from the market. Take stock of what else is needed and make shopping list.
~2b (about once a month): Take list with me to discount store (we have a Big Lots nearby) and check what’s available. I usually buy staples (mayo, pasta, etc.) and cereal and other packaged foods here, of course looking for the most nutritious available (don’t buy crap just because it’s cheap). There are often multiple organic products available.
~2c (about once a month): Stock up on fresh meat and specialty items from Whole Foods, and any fresh produce I might not have gotten at the farmers market (especially in the winter).
~3: go to Target or other grocery store for whatever’s left on the list (generally not much).

The keys to this are keeping a running shopping list, buying from the producer as much as possible, seldom paying retail/middle-man prices, looking for discount/clearance/sale items, and simply waiting to buy certain things until they are cheap (and stocking up when they are). Also necessary is actually cooking food myself rather than buying packaged- it’s much cheaper and more nutritious. If I were stricter about that and cut out ALL packaged food (oatmeal vs. cold cereal), I am certain I could cut our grocery expenses down by as much as 25%.

Keep at it, you can do it! We are seeing successes too, little by little!